BRANCHED-CHAIN AMINO ACIDS Overview Information

Branched-chain amino acids are essential nutrients that the body obtains from proteins found in food, especially meat, dairy products, and legumes. They include leucine, isoleucine, and valine. “Branched-chain” refers to the chemical structure of these amino acids. People use branched-chain amino acids for medicine.

Branched-chain amino acids are used to treat amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease), brain conditions due to liver disease (chronic hepatic encephalopathy, latent hepatic encephalopathy), a movement disorder called tardive dyskinesia, a genetic disease called McArdle's disease, a disease called spinocerebellar degeneration, and poor appetite in elderly kidney failure patients and cancer patients. Branched-chain amino acids are also used to help slow muscle wasting in people who are confined to bed.

Some people use branched-chain amino acids to prevent fatigue and improve concentration.

Healthcare providers give branched-chain amino acids intravenously (by IV) for sudden brain swelling due to liver disease (acute hepatic encephalopathy) and also when the body has been under extreme stress, for example after serious injury or widespread infection.

How does it work?

Branched-chain amino acids stimulate the building of protein in muscle and possibly reduce muscle breakdown. Branched-chain amino acids seem to prevent faulty message transmission in the brain cells of people with advanced liver disease, mania, tardive dyskinesia, and anorexia.

BRANCHED-CHAIN AMINO ACIDS Uses & Effectiveness

Anorexia. Taking branched-chain amino acids by mouth seems to reduce anorexia and improve overall nutrition in older, undernourished people. There is also early evidence that taking branched-chain amino acids by mouth might be helpful for people with anorexia that is associated with cancer or liver disease.

Poor brain function related to liver disease. Although there are some conflicting results, most research suggests that taking branched-chain amino acids by mouth can improve liver and brain function in people with poor brain function caused by liver disease.

Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease). Early studies showed promising results, but more recent studies show no benefit of branched chain amino acids in people with ALS. In fact, taking branched-chain amino acids might make lung function worse and increase the risk of death in people with this condition.

Liver disease caused by alcohol. Early research suggests that taking branched-chain amino acids daily along with a controlled diet does not reduce the risk of death in people with liver disease caused by drinking alcohol.

Athletic performance. There is inconsistent evidence about the effectiveness of branched-chain amino acids for athletic performance. Many studies suggest that taking branched-chain amino acids does not enhance exercise or athletic performance. However, other research suggests that it might reduce tiredness and muscle soreness associated with exercising.

Diabetes. Early research suggests that eating carbohydrates with an amino acid/protein mixture might improve insulin response in people with diabetes. However, it is not known if taking branched-chain amino acids as a supplement will provide the same benefits.

Liver cancer. Research suggests that drinking a beverage containing branched-chain amino acids daily for one year does not improve survival after surgical removal of liver cancer.

Liver cirrhosis. It is not clear if branched-chain amino acids benefit people with liver cirrhosis, the final phase of long-term liver disease. Early research suggests that branched-chain amino acids provide no benefit. However, there is some research that suggests branched-chain amino acids might improve quality of life in people with liver cirrhosis.

Genetic disorder that increases phenylalanine in the blood (Phenylketonuria). Taking branched-chain amino acids for up to 6 months seems to improve attention in children with phenylketonuria.

Disease of the spine called spinocerebellar degeneration (SCD). There are conflicting results about the effects of branched-chain amino acids in people with a disease of the spine called SCD. Some early research suggests that taking branched-chain amino acids by mouth might improve some symptoms of SCD. However, other research suggests that branched-chain amino acids do not improve muscle control in people with SCD.

Preventing fatigue.

Improving concentration.

Preventing muscle wasting in people confined to bed.

Other conditions.

More evidence is needed to rate the effectiveness of branched-chain amino acids for these uses.

BRANCHED-CHAIN AMINO ACIDS Side Effects & Safety

Branched-chain amino acids are POSSIBLY SAFE when taken by mouth appropriately. Some side effects are known to occur, such as fatigue and loss of coordination. Branched-chain amino acids should be used cautiously before or during activities where performance depends on motor coordination, such as driving.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking branched-chain amino acids if you are pregnant or breast feeding. Stay on the safe side and avoid use.

Children: Branched-chain amino acids are POSSIBLY SAFE for children when taken by mouth, short-term. Branched-chain amino acids have been used safely in children for up to 6 months.

Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease): The use of branched-chain amino acids has been linked with lung failure and higher death rates when used in patients with ALS. If you have ALS, do not use branched-chain amino acids until more is known.

Branched-chain ketoaciduria: Seizures and severe mental and physical retardation can result if intake of branched-chain amino acids is increased. Don’t use branched-chain amino acids if you have this condition.

Chronic alcoholism: Dietary use of branched-chain amino acids in alcoholics has been associated with liver disease leading to brain damage (hepatic encephalopathy).

Low blood sugar in infants: Intake of one of the branched-chain amino acids, leucine, has been reported to lower blood sugar in infants with a condition called idiopathic hypoglycemia. This term means they have low blood sugar, but the cause is unknown. Some research suggests leucine causes the pancreas to release insulin, and this lowers blood sugar.

Surgery: Branched-chain amino acids might affect blood sugar levels, and this might interfere with blood sugar control during and after surgery. Stop using branched-chain amino acids at least 2 weeks before a scheduled surgery.

BRANCHED-CHAIN AMINO ACIDS Interactions

Branched-chain amino acids might decrease how much levodopa the body absorbs. By decreasing how much levodopa the body absorbs, branched-chain amino acids might decrease the effectiveness of levodopa. Do not take branched-chain amino acids and levodopa at the same time.

Branched-chain amino acids are used to help make proteins in the body. Taking Diazoxide along with branched-chain amino acids might decrease the effects of branched-chain amino acids on proteins. More information is needed about this interaction.

Branched-chain amino acids are used to help make proteins in the body. Taking drugs called glucocorticoids along with branched-chain amino acids might decrease the effects of branched-chain amino acids on proteins. More information is needed about this interaction.

Thyroid hormone interacts with BRANCHED-CHAIN AMINO ACIDS

Branched-chain amino acids help the body make proteins. Some thyroid hormone medications can decrease how fast the body breaks down branched-chain amino acids. However, more information is needed to know the significance of this interaction.

BRANCHED-CHAIN AMINO ACIDS Dosing

The following doses have been studied in scientific research:

BY MOUTH:

For a brain condition due to liver disease (hepatic encephalopathy): 240 mg/kg/day up to 25 grams of branched-chain amino acids.

For mania: a 60 gram branched-chain amino acid drink containing valine, isoleucine, and leucine in a ratio of 3:3:4 every morning for 7 days.

For tardive dyskinesia: a branched-chain amino acid drink containing valine, isoleucine, and leucine at a dose of 222 mg/kg taken three times daily for 3 weeks.

For anorexia and improving overall nutrition in elderly malnourished hemodialysis patients: granules of branched-chain amino acids consisting of valine, leucine, and isoleucine at a dose of 4 grams taken three times daily.

The estimated average requirement (EAR) of branched-chain amino acids is 68 mg/kg/day (leucine 34 mg, isoleucine 15 mg, valine 19 mg) for adults. However, some researchers think earlier testing methods may have underestimated this requirement and that the requirement is really about 144 mg/kg/day. Other researchers think the EARs for children are also low. EARs for branched-chain amino acids for children are: ages 7-12 months, 134 mg/kg/day; 1-3 years, 98 mg/kg/day; 4-8 years, 81 mg/kg/day; boys 9-13 years, 81 mg/kg/day; girls 9-13 years, 77 mg/kg/day; boys 14-18 years, 77 mg/kg/day; girls 14-18 years, 71 mg/kg/day.

Institute of Medicine. The role of protein and amino acids in sustaining and enhancing performance. Washington, DC: National Academy Press, 1999. Available at: http://books.nap.edu/books/0309063469/html/309.html#pagetop

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